I agree with the previous poster. On the flip side, any aspect of teeth kills any technique used. Beyond that, no hands,,,initially. OP stated that "some guys needs hands for it to work". When you say work, do you mean get hard, or climax? Hands certainly help to get me there, but if I want to enjoy it, only use hands sparingly (as another stated, to hold it while licking, slapping tongue, rubbing on face, etc). Once its time to work on the finish, use your hands to your hearts content.
For me, the balls are just as important to the experience. Those who spend equal time there get my highest marks. Hard licking and mouth cradling, not golf ball sucking. And cat licking the underside (frenulum) is exquisite. Keep it wet throughput. Dont be afraid to make a mess. Last, while spit versus swallow doesnt technically matter, the sight and submission of swallowing is the icing on the cake!